1. Field of the Invention
The present invention relates to an organic light emitting element comprising an anode, a cathode, and a layer containing an organic compound that emits light by being applied with an electric field (hereinafter, referred to as an electroluminescent layer), and a light emitting device using the same. In particular, the invention relates to an electronic appliance mounted with a light emitting display device, which comprises a TFT and an organic light emitting element, as a component part.
In the present specification, a light emitting device indicates an image display device, a light emitting device, a light source (including a lighting device), and the like. The light emitting device further includes all of a module in which a light emitting device is attached with a connector, e.g., an FPC (flexible printed circuit), a TAB (tape automated bonding) tape, or a TCP (tape carrier package); a module having a printed wiring board provided on an end of a TAB tape or a TCP; and a module in that a light emitting element is directly mounted with an IC (integrated circuit) by the COG (chip on glass) technique.
2. Description of the Related Art
In recent years, a research related to a light emitting device having an EL element as a self-luminous light emitting element has been activated. Such a light emitting device is also referred to as an organic EL display or an organic light emitting diode. The light emitting device has advantages of being high-speed response that is suitable for displaying moving images, low voltage, low power consumption drive, and the like. Therefore, the light emitting device has been attracting attention as a next generation display device such as a new generation cellular phone and personal digital assistance (PDA).
An EL material for forming an EL layer is very easily deteriorated. In particular, the EL material is easily deteriorated due to existence of oxygen or moisture, and therefore, the EL material had drawbacks in which luminance of a light emitting element is lowered and life thereof is shortened.
Conventionally, moisture etc. has been prevented from penetrating into a light emitting element as follows: the light emitting element is covered with a sealing can while an inert gas is filled in the interior of the sealing can and a drying agent is pasted therein.
The present applicant discloses a structure in which a pair of substrates is attached to each other with a sealing material and a portion surrounded by the sealing material is filled with a resin to encapsulate a light emitting element in patent document 1.
The present applicant further discloses a structure in which a pair of substrates is attached to each other by using a filler to encapsulate a light emitting element in patent document 2.
The present applicant still further discloses a light emitting element in which a columnar spacer is provide between a pair of substrates in patent document 3.
[Patent Document 1]: Japanese Patent Application Laid-Open No. 2001-203076
[Patent Document 2]: Japanese Patent Application Laid-Open No. 2001-93661
[Patent Document 3]: Japanese Patent Application Laid-Open No. 2000-196438